Hydrogen storage performance of a pseudo-binary Zr-V-Ni Laves phase alloy against gaseous impurities

This work illustrates the hydrogen storage performance of Zr(V0.95Ni0.05)2 Laves phase alloy in hydrogen with/without gaseous impurities. It is found that Zr(V0.95Ni0.05)2 can be activated in either pure hydrogen or hydrogen with 1.00 vol% O2. However, the activation of Zr(V0.95Ni0.05)2 in hydrogen with gaseous impurities requires much more time and higher temperature due to the continually forming passivation layer oxides. Hydrogen storage capacity is found to degrade evidently with increasing oxygen content and the alloy almost loses entire hydrogen absorption capacity in hydrogen with 2.00 vol% O2. During absorption/desorption cycles, the maximum hydrogen capacity against gaseous impurities decreases in various degree comparing to that in pure hydrogen. At the temperature below 423 K, the hydrogen desorption capacity decreases gradually with increasing absorption/desorption cycles. The alloys can hardly absorb hydrogen in the third cycle both at 308 and 423 K. With the further increase of temperature, the hydrogen absorption capacity at the first cycle even shows a little rise at 573 K comparing with that at 308 K, indicating a strong temperature dependence of the hydrogen storage degradation against gaseous impurities. Both the kinetics and capacity of Zr(V0.95Ni0.05)2 decrease to a certain extent after 3 absorption/desorption cycles at 723 K.